Continuously rotating vertical casting machine



L. BABEL ETAL I 3,430,684

March 4, 1969 v CQNTINUOUSLY ROTATING VERTICAL CASTING MACHINE Filed Feb. 28. 1966 I of 4 Sheet FIG 'I March 4, 1969 L. BABEL ETAL I 3,430,684

CONTINUOUSLY ROTATING VERTICAL CASTING MACHINE Filed Feb. 28. 1966 I Sheet 2 of 4 CONTINUOUSLY ROTATING VERTICAL CASTING MACHINE Filed Feb. 28, 1966 L. BABEL ETAL March 4, 1969 Sheet FIG. 3

March 4, 1969 L. BABEL ETAL CONTINUOUSLY ROTATING VERTICAL CASTING MACHINE Filed Feb. 28, 1966 Sheet United States Patent CONTINUOUSLY ROTATING VERTICAL CASTING MACHINE Louis Babel, Sauvigny-les-Bois, and Pierre Peytavin, Aulnoye-Aymeries, France, assignors to Societe Civile dEtudes de Centrifugation Filed Feb. 28, 1966, Ser. No. 530,680

Claims priority, application France, Mar. 3, 1965,

US. Cl. 164-482 Claims Int. Cl. B22d 11/02 ABSTRACT OF THE DISCLOSURE It is conventional to produce solid or tubular castings from molten metal which are directly solidified in the shape of a desired article.

The present invention relates to a machine for use in the continuous casting of solid or hollow castings, which are preferably circular in section, and are formed in rotating molds.

This continuous rotary casting process produces excellent results, even in the particularly difficult cases in which the solid or tubular casting is to be circular in section.

However, certain difficulties are encountered in carrying out this process, which are overcome by the use of the machine according to the invention.

The difficulties encountered in removing the casting are of several kinds.

On the one hand, the casting turns at a substantial speed and is therefore subjected to a centrifugal effect which tends to displace the casting from the axis of rotation of the mold and cause movements which will adversely affect the formation of the casting during its solidification to an extent sufficient to seriously interfere with the operation.

On the other hand, since continuous rotary casting is carried out in a vertical position and the time required for cooling is substantial, it is necessary to provide rotary casting machines which are quite tall. This substantial length, coupled with the unavoidable differences in temperature, can cause deformations of the machine which make it particularly difficult to guide the casting with suflicient accuracy.

The present invention relates to a machine which makes it possible to regulate the speed at which the cast ing descends while simultaneously guiding it on its course, without imposing any strains on it which might adversely affect the quality of the end product.

The object of the present invention is to provide a machine for advancing and guiding metallic castings which are being formed by a continuous rotary process, said machine being essentially characterized by the fact that the speed of travel of the casting is controlled by at least one pair of rollers which bear against the casting. These rollers are driven at a predetermined speed and may be moved symmetrically away from the axis of the casting. This pair of rollers is mounted in a rigid cage which rotates about the axis of the casting at the same speed as the casting itself. This cage is preferably mounted on two ball bearings, at least one of which may be moved toward and away from the axis of the casting in a plane perpendicular to said axis.

In a preferred embodiment of the invention the machine comprises two pairs of driving rollers, one above the other. A weight carried by a lever pivotally mounted to swing about a fixed point counterbalances the effect of centrifugal force on each roller and its support during their rotation. These rollers may swing about a horizontal axis in such a manner as to vary the distance between the two rollers of each pair in proportion to any changes in the diameter of the casting.

In one embodiment of the invention the rollers of each pair are kept in a symmetrical position relative to the axis of the casting, even though movable toward and away from each other, by fastening the supports for the rollers to two rods which are pivotally mounted on the ends of two swing bars pivotally attached at two points on opposite sides of the casting.

In another embodiment the rollers of each pair are kept symmetrical with respect to the axis of the workpiece while being moved toward and away from each other because each roller support is fastened to a toothed sector which engages an identical toothed sector fastened to the support for the other roller of the same pair.

In a preferred embodiment of the invention the two roller supports of each pair are connected by a strap resiliently mounted on the roller supports so that the rollers are kept at a certain distance apart unless the casting exerts against the rollers a predetermined separating force greater than that which the rollers can exert without being further separated.

In one embodiment of the invention, each driving roller is fixed to a coaxial gear driven by a drive shaft about which the support for that roller swings.

In a first embodiment of the invention the drive rollers mounted as hereinbefore described receive the casting immediately after it has been formed, but preferably after the casting has been vigorously cooled.

When jets of water are used for this cooling, it is desirable to mount the nozzles through which the water is sprayed on an auxiliary device capable of rotating the nozzles about the casting at an angular speed different from that of the casting so that the periphery of the casting is uniformly cooled. This precludes mounting these nozzles on the cage which carries the drive rollers.

In accordance with the invention it is equally desirable, in this first embodiment, to provide near the bottom of the machine at least one pair of free guide rollers which are mounted to move away from each other as necessary so as to permit an unusually thick section of the casting to pass by, but which nevertheless prevent the casting from swinging out of plumb.

In a second embodiment of the invention, which is particularly designed for use when the castings are to be rapidly produced, suitable cooling means (Water jets for example) which may be stationary, or mounted to turn at a speed different from that of the casting, are provided at the top of the mold. Several pairs of freely rotating guide rollers are positioned below the cooling apparatus and mounted to separate while remaining in symmetrical positions relative to the axis of the casting when the casting exerts thereagainst a force exceeding a predetermined value, each of said pairs of guide rollers being driven around the axis of the casting at the same angular speed at which the casting rotates.

Depending on the height required by the cooling equipment and the spacing of guide rollers required to keep the casting in the proper line, guide rollers may be positioned in the cooling zone, between the mold and the driving means.

The guide rollers are mounted to turn freely so as to conform to the motion of the casting resulting from its rotation and its speed of descent, so as to avoid causing any strain on the casting other than that required to keep it in line with the vertical axis of the machine.

Below the guide rollers are the drive rollers which have the same characteristics as those which have been described and are of course also driven about the axis of the casting at the same angular speed at which the casting turns.

In order that the invention may be more clearly understood, several embodiments thereof will now be described, purely by way of example, with reference to the accompanying drawings, in which:

FIG. 1 is a schematic vertical section taken through a first embodiment of the machine according to the invention;

FIG. 2 is a schematic vertical section taken through a second embodiment of this machine;

FIG. 3 is a schematic sectional view taken along the line III-III of FIG. 4, showing the means for driving the rollers;

FIG. 4 is a schematic sectional view taken along the line IVIV of FIG. 3, showing how the driving rollers are mounted;

FIG. 5 is a top plan view of a device for separating the two rollers of a pair while still keeping them symmetrically positioned relative to the axis of the casting; and

FIG. 6 is a sectional view on an enlarged scale taken along the line VI-VI of FIGURE 5 and showing the resilient mounting of the strap which connects the two rollers of each pair.

The upper part of FIG. 1 shows a mandrel 1 which is introduced into the rotating mold 2 when hollow castings are to be produced.

The pipe 3, through which cold water is supplied to the inside of the mandrel 1, and the pipe 4 through which the water leaves the mandrel, are both schematically shown.

The mandrel 1 is supported by a carriage 5 which is vertically slidable in a stationary framework 6 and actuated by a hydraulic cylinder 7 (schematically shown) by means of which the mandrel may be lifted at will.

FIG. 1 also shows schematically the worm and tangent gear drives 8 which rotate the mandrel at an angular speed substantially equal to that of the mold 2 and also adjust within certain limits the eccentricity of the axis of the mandrel relative to that of the mold, as well as the angular direction of said eccentricity.

Such a device for regulating the position of the mandrel relative to that of the mold is described in French Patent No. 1,329,048.

The chute 9 through which the molten metal is fed to the mold is also schematically illustrated in FIG. 1.

The described embodiment comprises two pairs of driving rollers, 10a, 10b, and 11a, 1112, which are mounted in a rigid cage 12 which turns on two roller bearings 13 and 14 shown schematically on the drawing.

The lower bearing 13 comprises a part-spherical race while the upper bearing 14 may be of the needle type. The mold 2 rotates in bearing 14 and the cage is fastened to the stationary portion of the machine through a ball joint.

The position of the spherical abutment 13 may be adjusted with respect to the platform 15 by which it is supported in order to bring about a perfect alignment of the various parts of the machine relative to the vertical axis of the casting.

For this purpose, the cage 13:: of the annular bearing race is held between fixed abutments 16 fastened to the platform 15 by screws 17 which make it possible to hold the cage 13 in different positions.

The cage 12 comprises a ring gear 18 which is driven by the gear 19 fixed to the shaft of the electric motor 20.

The speed of rotation of the cage 12 around the shaft of the casting 21 is equal to the speed of rotation of the mold 2, when the mold is fixed to the carriage 12, or even when the mold is mounted independently of the cage 12, in which case the mold is driven at the same speed by any suitable means.

In the latter case, it is within the scope of the invention to rotate the mold at a speed different from that of the casting, if this is considered desirable.

Reference numeral 22 indicates a cooling device for projecting water onto the casting after it leaves the mold 2.

In accordance with the invention the cooling means 22 is mounted on means not shown which permits the device 22 to be held stationary or turn at a speed of rotation different from that of the casting so as to rapidly cool its surface.

In the embodiment shown in FIG. 1 the cage 12 also carries at its lower end a pair of guide rollers 23a and 23b turning loosely on their axes.

The manner in which the driving rollers and guide rollers are mounted will be hereinafter described in greater detail.

FIG. 2 schematically illustrates a second embodiment of the machine according to the invention, used to make solid cylindrical castings. However, the machine illustrated in FIG. 2 could be used to make hollow castings, and the machine illustrated in FIG. 1 could be used to produce solid castings.

FIG. 2 shows schematically the rotating mold 2, the cooling means 22 (which in this case comprises nozzles for projecting water which are fixed to the framework of the machine and are consequently stationary) and three pairs of guide rollers 23, as well as two pairs of drive rollers 10 and 11 mounted on a cage 12 which turns on bearings 13 and 14. The cooling means for projecting water extends from the bottom of the mold 2 to the cage for the drive rollers, the guide rollers being regularly spaced over this interval and the water projecting nozzles being positioned between the guide rollers.

FIG. 2 also shows how the mold 2, guide rollers 23 and drive rollers 10 and 11 are driven by the motor 24 through gears mounted on the shaft 25 and additional gears fixed to the driven members.

It is clear, however, that it would be within the scope of the invention to drive the driven members from independent motors.

FIGS. 3 and 4 show how the driving rollers are mounted.

FIG. 4 shows the rollers 10a, 10b, 11a and 11b of FIGS. 1 and 2.

Each roller is mounted on a support 26 pivotally attached to the cage 12 by means of a shaft 27.

The supports for the rollers 10a and 11a are pivotally mounted on the same shaft 27, as are the two supports for the rollers 10b and 11b.

A counterweight 28 pivotally attached at 29 to the cage 12 is fixed to a lever 30 connected through a rod 31 to the support 26 for each roller.

When the carriage 12 is rotated about the axis of the casting the weight 28, which is urged in the direction of the arrow F by centrifugal force, exerts a force against the support 26 for the roller which acts in the direction of the arrow F in the opposite direction from that in which centrifugal force acts on the roller 10 and its support 26.

It is clear that by judiciously selecting the relative weights of the different members, as well as the lengths of the different moment arms, it is possible to almost completely compensate the moving parts of this mechanism for the effects of centrifugal force, which ceases to have any substantial influence on the distance between rollers lilo-10b and Ila-11b.

FIG. 3 shows schematically how the rollers are driven at a given speed.

FIG. 3 also shows how the supports 26 of the two rollers b and 11b are pivotally mounted on a shaft 27 mounted on the carriage 12, only a small part of which is shown in FIG. 3.

The shaft 27 is driven by a motor 32, which is schematically represented, and a worm and tangent gear transmission 33.

The axles 34 and 35 of the rollers 10b and 1112 each carry a gear 36 which engages a pinion 37 fixed to the shaft 27.

It will be appreciated that the motor 32 drives the drive rollers 10b and 11b, but that the supports 26 for these rollers may nevertheless swing freely about the shaft 27.

Taking into account the relatively small amplitude through which the supports 26 can swing about the shaft 27, as well as the very slow angular speed of these movements, this swinging has no practical influence on the speed of rotation of the driving rollers 10]) and 11b.

The two rollers 10a and 11a are driven in an analogous manner and at the same speed.

FIG. 5 shows the mechanism which insures that the rollers will move symmetrically and the device which resists their separating.

As shown on FIG. 5 the drive rollers 10a and 10b are each mounted on their support 26 which is pivoted on axle 27 not shown on FIG. 5.

Two swinging bars 38 and 39 are pivotally mounted at their centers on pins 40 fixed to the cage 12.

The ends of the swinging bars 38 and 39 are connected by bars 41 and 42 which have been shown as unitary bars for the sake of simplicity but may in practice comprise a plurality of articulated segments if this is necessary to produce a desired kinematic effect.

It will be appreciated that any movement of the bar 41 results in an equal and opposite movement of the bar 42.

The support 26 for the rollers 10a is connected by a rod 43 to the bar 42, while the support 26 for the roller 10b is connected in the same way by rod 44 to the bar 41.

It follows that the rollers 10:: and 11b may move away from each other, but must remain symmetrically positioned with respect to the axis of the casting 21, which is thus automatically guided and cannot leave the straight path which it should follow.

The pressure exerted by the two rollers 10a and 10b on the casting is produced by a strap 45 connected at its ends to two resilient devices 46 carried at the tops of the roller supports 26.

One of the resilient devices is shown in section on a larger scale on FIG. 6 which shows the strap 45 as well as the member 47 which is pivotally connected to the support 26 of the roller 10a, thus permitting said supports to swing.

A rod 48 provided with a shoulder 49 has a threaded part 50 screwed into the member 47, while a shoulder 51a on the cup 51 bears on the edge of a hole in the strap 45.

The rod 48 supports a sleeve 52 which carries a set of resilient dished washers 53 which are retained between a flange 52a on the sleeve and a stop 54 keyed to the sleeve 52.

When the resilient washers 53- are mounted on the sleeve they may be assembled in a more or less compressed condition, depending on the operating conditions expected to be encountered.

It follows from what has just been described that when the rod 48 is turned by a key engaging the square end 48a of this rod, the distance between the member 47 and the end of the strap 45 may be adjusted at will, thus regulating the distance between the two rollers 10:: and 10b when at rest. v

It should further be noted that this adjustment of the space between the rollers may be carried out without exerting any pressure on the set of washers 53.

Since two members 46 have been provided for the sake of symmetry, it is of course desirable, in order to equalize the effects of centrifugal force, to position the strap 45 symmetrically with respect to the casting 21.

So long as the force exerted on the casting by the rollers 10a and 10b is not great enough to further deform the resilient washers 53, the rollers 10a and 10b remain at the same distance from each other.

On the other hand, when the force exerted by the casting on the rollers exceeds a predetermined value, the resilient washers are additionally compressed, thus permitting a symmetrical separation of the rollers 10a and 10b to permit a temporarily excessive thickness of the casting.

The force which has been exerted on the resilient washers 53 to compress and hold them in place on the sleeve 42 must correspond exactly to the force which the casting 21 should exert against the rollers 10a and 10b in order to begin to move them further apart.

Under these circumstances, the use of the device according to the invention makes it possible to determine both the force exerted by the rollers on the casting and the force which these rollers continue to exert on the casting when they are separated by a given distance.

Moreover, it is clear that if the initial adjustment is such that the spacing of the rollers 10a and 10b is equal to or slightly greater than the normal diameter of the casting, the guide rollers will not become effective as long as the casting remains in its normal position, but will act to return the casting to its proper vertical position whenever it departs therefrom. Moreover, these guide rollers will not prevent the passage of an unusually thick section of the casting.

Guide rollers of this type are provided, for example, at 23, 23a, and 23b in the two embodiments of the invention which have been hereinbefore described.

From the foregoing description it will be seen that the machine according to the invention makes it possible to very effectively regulate the operating or casting speed of a rotating casting, while guiding it as strictly as necessary.

It should, however, be noted that the casting is nevertheless guided by means sufficiently flexible to avoid atlording abrupt resistance to the passage of those temporarily distorted portions of the casting which are necessarily produced in all continuous rotary casting processes. This latter characteristic of the machine is particularly valuable, because applicants experience has indicated that too strict guiding of a casting may subject it to strains sufficient to cause faults in the final product, or even stop the casting because the casting becomes caught in the mold, followed by leakages of liquid metal below the mold.

The embodiments which have been described have been given purely by way of example and may be modified as to detail without thereby departing from the basic principles of the invention. In particular, it is clear that guide rollers may be used which are in groups other than pairs, such for example as sets of three rollers, or are positioned at three or more points equidistant from each other and the axis of the casting so as to converge toward it.

What is claimed is:

1. -In a rotary continuous casting machine, apparatus for advancing and guiding the castings produced by said machine along a vertical axis, said apparatus comprising a cage mounted to rotate about said axis, means for rotating said cage at the same speed as said casting, and a plurality of pairs of rollers mounted in said cage, means mounting the two rollers of each pair symmetrically with respect to said vertical axis, each roller being mounted to swing about a different one of two axes lying in the same plane perpendicular to said vertical axis, the two rollers of each pair being mounted to apply equal pressure to diametrically opposite areas of said casting, and at least one pair of rollers being driven and axially advancing said casting, and means applying to said rollers a force urging them radially inward which is equal to the centrifugal force urging them radially outward which results from rotation of said cage.

2. A machine as claimed in claim 1 in which said guide rollers are mounted to swing about a fixed point and comprising a counterweight connected to each guide roller to urge each roller in one direction about said fixed point with a force equal to that exerted by centrifugal force on said roller to urge it in the opposite direction about said fixed point.

3. A machine as claimed in claim 2 comprising parallel motion linkage which constrain the rollers of each pair to diametrically opposed positions on opposite sides of said axis.

4. A machine as claimed in claim 2 comprising a set of intermeshing toothed members which constrain the rollers of each pair to diametrically opposed positions on opposite sides of said axis.

5. A machine as claimed in claim 2 comprising individual supports for each roller, together with means connecting the supports of each pair, said connecting means comprising a resilient component.

References Cited UNITED STATES PATENTS FOREIGN PATENTS Great Britain. Great Britain. Great Britain. France.

I. SPENCER OV-ERHOLSER, Primary Examiner.

R. SPENCER ANNEAR, Assistant Examiner.

US. Cl. X.R. 

